Borussia Dortmund reduced the gap to leaders Bayern Munich to seven points with a 1-0 home win over Arminia Bielefeld in the Bundesliga on Sunday. Erling Haaland, linked heavily with a July move to Manchester City in the British media this weekend, was back in the squad for the first time in seven weeks due to injury. But the Norway striker started on the bench and it was Marius Wolf who netted his second of the campaign from Thorgan Hazard’s cross in the first half. “It doesn’t always have to be a spectacle,” Wolf told reporters. “I think we did our homework today. The most important thing is…